These sites are mentioned elsewhere on this site but these all include notes and exercises on Algebra. Answers are included in these resources and of course you can check answers on WolframAlpha.
Note there are resources for older students further down the page.
For younger students (age 11-16) try the Interactive Tutorials from The Centre for Innovation in Mathematics Teaching, (CIMT).
Fundamental Skills Function Machines Linear Equations Basic Factorising
Expansion – Single Brackets Linear Equations with Brackets
Factorising Expressions Substitution into Formulae 1 Substitution into Formulae 2
Linear Equations 1 Linear Equations 2
Coordinates Plotting Straight Lines Graphs and Gradients
Laws of Indices Negative Indices Fractional Indices
Straight Line Graphs Linear Equations Parallel and Perpendicular Lines
Simultaneous Equations Equations in Context
Equations, Formulae and Identities Simplifying Expressions Factorising Using Formulae
Quadratic Equations: Factorisation and by Completing the Square
The following example – note the colours shows how to expand three brackets.
You could check your answers on WolframAlpha and change the query to make up your own examples.
The Maths Teacher (age 11-17)
David Smith’s site, The Maths Teacher has an extensive collection of videos to help you study Mathematics. GCSE (age 14-16, though many of these resources would be helpful for younger students also) and A-Level (age 16-18) lessons are available. For each topic not only is a video available but also a transcript and exercises with worked solutions. This makes the site ideal for revision – you have the choice of perhaps just trying the exercises or if you feel you need more help you can watch the video – whatever is right for you.
For older students who have already studied many topics in Algebra, CIMT’s Step Up to A Level Maths includes notes and examples on Basic Algebra, Quadratic Functions and Equations and Inequalities. These exercises could also be used by GCSE students aiming for the highest grades. Another very useful publication is the Algebra Refresher from The Mathcentre which has many questions with the answers provided at the end of the document. Also from the Mathcentre you can view all the topics available – several different resource types such as notes and videos are available for each topic.
Sections 1 (Basic Algebra) & 3 (Equations, Inequalities and Partial Fractions) of the very helpful Helm Workbooks include worked examples and exercises (with answers).
For videos try the following sites:
Exam Solutions A Level Maths (select your exam board from A Level Maths tab)
and note The Mathcentre, already mentioned above.